Researchers from the University of Alicante in Spain have analyzed ten brands of cigarettes and found that the concentrations of certain harmful and carcinogenic substances vary significantly from one brand to another. Until now legislation has not covered these other toxic compounds and have only established limits for nicotine, tar and carbon monoxide. Scientists have also developed better catalysts/filters to reduce the harmful products in tobacco.

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As of 2000, smoking is practiced by some 1.22 billion people, of which men are more likely to smoke than women, poor more likely than rich, and people in developing countries or transitional economies more likely than people in developed countries. As of 2004, the World Health Organization (WHO) reports that of the 58.8 million deaths occurring globally, 5.4 million are tobacco-attributed.

In accordance with current legislation, cigarette packets indicate the nicotine, tar and carbon monoxide concentrations in order to confirm that these do not exceed permitted levels. However the quantity of these substances is not always proportional to the toxicity levels of many other compounds¸ "therefore more suitable parameters are required for determining the toxicity level of tobacco". This is a conclusion of a study by chemical engineers at the University of Alicante (Spain), published in the journal Food and Chemical Toxicology.

The researchers analysed the gases and particulate matter —tar— from ten commercial brands of blond tobacco cigarettes:seven American or British brands (Marlboro, Winston, Chesterfield, Camel, L&M, Lucky Strike and John Player) and three Spanish brands (Fortuna, Ducados and Nobel). "Although the products generated appear similar, the relative performance (mg/cigarette) of certain highly toxic and carcinogenic compounds varies considerably from one brand to another", states María Isabel Beltrán, one of the authors.

The results also reveal that the brands with the lowest production of gaseous compounds are not those with the lowest tar levels, and that the brand that generates the most isoprene, toluene and chrotonaldehyde (not regulated compounds) produces a lower quantity of tar than the average.

"We should not therefore assume that a cigarette which generates more tars is going to be more toxic than another that produces fewer", notes Beltrán.

The researchers, who claim in the article not to have any conflict of interests, have preferred not to reveal the figures for each brand and have identified them with the letters A to J. To perform the analysis the cigarettes were inhaled in a smoking machine and the smoke composition was measured in three fractions: one gaseous, in which 35 compounds were identified, and two of particulate matter, with 85 compounds, which were trapped respectively in the filter and in the smoke traps used to measure "what a person smokes".

It has, therefore, been observed that in the cigarettes containing more tobacco, the amount consumed in a set number of puffs is lower. According to the scientists, this is because there is less oxygen available due to the increased packing.

The amount of nicotine in the traps varies from 0.28 to 0.61 mg/cigarette, that is, the amount may double from one brand to another, while remaining within legal limits.

Beltrán states. "Of the more than three thousand compounds in tobacco there are many which are worse, such as hydrogen cyanide, 1,3-butadiene or some of the families of aldehydes, nitrosamines and phenols".

To reduce the quantities of toxic products in the cigarettes, the researchers have also tested and developed several catalysts to reduce these toxins. One of these, known as Al-MCM-41, reduces carbon monoxide emissions by 23% and nicotine emissions by more than 40%.

"The three-dimensional structure of this material, clay with silicon and aluminum oxides, permits the formation of caves in which the long chain compounds are retained", says Beltrán, who confirmed that the flavor of the tobacco is hardly affected and that some of the leading companies have already expressed interest in the patent for the new catalyst.